Deep rolling apparatuses and deep rolling systems have been known in the art for many years. Prior art deep rolling systems generally use a lower tool in conjunction with an upper tool to deep roll compressive stresses into a crankshaft, for use in vehicles and other applications, increasing the strength around lobes or cams on the crankshaft. The need for deep rolling is becoming ever more important because automotive vehicles and components are being downsized to reduce weight and improve fuel efficiency; accordingly, smaller engines and crankshafts are increasingly needed. With smaller engines and crankshafts, made with less material than older, more robust designs, there is a need to improve the crankshaft's fatigue strength and durability. This improved fatigue strength and durability is accomplished through deep rolling of the fillets or lobes and other circular joint areas along the crankshaft. The strength and durability of crank pins of the main bearing journals can be significantly increased by forming compressive stresses into the annular fillets between the pin journals and the adjacent counter weights, or balancing webs on the crankshaft.
Some prior art lower tools use a system of rollers to support and roll the crankshaft while the upper tool employs work rolls that actually do the strengthening and finishing of the work piece. Other types of lower work tools also include work rolls which assist in forming the compressive stresses, along with the upper tool. In such a design, back up rollers operate to rotatably support the work rolls, which are held in place by a cage retainer and cage.
Relatively high mechanical forces are necessary to sufficiently compress/stress the work piece. As is well know in the mechanical arts, applications using higher forces tend to cause moving parts to wear out relatively more quickly than in designs using more modest forces. In a typical deep rolling operation, the work rolls and support rollers are encased in a modular tool that is supported in a housing. When servicing of any of the tool components is necessary, processing is stopped and the tools are disassembled from their respective housings for servicing and/or replacement. Accordingly, this halt in production has associated expenses relating to process down time, and is relatively labor intensive.
Therefore, there is a need in the art for a faster and easier way to replace or repair deep rolling tools.